serum creatinine

Since creatinine clearance is faster than urea, the blood creatinine content is increased after urea is increased. Simultaneous determination of blood urea and creatinine has its unique clinical significance. When the kidney is slightly damaged, the increase in serum urea is significantly greater than that in the muscle liver, while the severe damage is the opposite. When severe tubular damage occurs, the ratio can be reduced to 20:1. Therefore, the determination of serum creatinine is more important than the blood urea in the diagnosis and treatment of end-stage renal disease. Basic Information Specialist classification: urinary examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Mainly seen in progressive muscle atrophy, anemia, leukemia and so on. Normal value: Serum creatinine (male): 44-133 μmol/L Serum creatinine (female): 70-106 μmol/L Above normal: High due to strong kidney reserve and compensatory capacity, serum creatinine is normal when early or mild glomerular filtration function is impaired. Only when the glomerular filtration function is reduced to 1/3 of normal people, serum creatinine is significantly increased, so it can not reflect the early impaired renal function, which is of great clinical significance for end stage renal disease. Simultaneous determination with BUN is more significant, both of which increase at the same time, indicating severe impaired renal function. When Cr>200μmol/L, the condition continues to deteriorate, and there is a tendency to develop uremia; >400μmol/L has a poor prognosis. If only BUN is elevated, and Cr is normal, it may be caused by extra-renal factors, such as gastrointestinal bleeding or urinary tract obstruction. negative: Positive: Tips: Serum creatinine determination is more important than blood urea in the diagnosis and treatment of end-stage renal disease. Normal value Male 44 ~ 133μmol / L, female 70 ~ 106μmol / L. Clinical significance 1, increased serum creatinine due to kidney reserve and compensatory ability, so early or mild glomerular filtration function is impaired, serum creatinine is normal. Only when the glomerular filtration function is reduced to 1/3 of normal people, serum creatinine is significantly increased, so it can not reflect the early impaired renal function, which is of great clinical significance for end stage renal disease. Simultaneous determination with BUN is more significant, both of which increase at the same time, indicating severe impaired renal function. When Cr>200μmol/L, the condition continues to deteriorate, and there is a tendency to develop uremia; >400μmol/L has a poor prognosis. If only BUN is elevated, and Cr is normal, it may be caused by extra-renal factors, such as gastrointestinal bleeding or urinary tract obstruction. 2, blood creatinine reduction, mainly seen in progressive muscle atrophy, anemia, leukemia and so on. Low results may be diseases: high anemia results may be diseases: renal failure, uremia considerations 1. When measuring creatinine, the temperature of each tube should be reduced to room temperature, and then colorimetric, because the temperature increase can make the color of bitter acid solution deeper, but the standard and measurement are not consistent. 2. In order to ensure accurate and reliable test results, each test should include quality control serum, and the measured quality control value should fall within the allowable range. 3, WHO recommended creatinine picric acid colorimetric method OCV is ± 0.4%, RCV is ± 8%, China's recommended RCV is 8%. 4, such as homemade quality control serum, should pay special attention to the infection of hepatitis virus, and do a good job of disinfection. 5, serum (pulp) if the day is not measured, can be stored in the refrigerator for 3 days, if not long-term, can be stored at -20 °C. 6, slight hemolysis can make creatinine determination results are high, severe hemolysis can interfere with the results. 7. The protein-free blood filtrate used for the determination of creatinine is affected by the pH value. When the pH value is below 2, the recovery rate can reach 100%. 8. Picric acid is toxic. Do not swallow or touch the skin. If it is inadvertently contacted, rinse it with plenty of water in time. 9, the quality of picric acid should be high: to use AR above the level of reagents, such as picric acid reagent is not pure, can increase the absorbance of the blank tube and affect the measurement results. 10. Colorimetric should be completed within 15 minutes after color development. If the time is too long, the non-specific reaction of picric acid with other substances in the blood filtrate will affect the accuracy of the determination results. 11. Bitter acid is an explosive. To prevent accidents, it is best to use plastic bottles and add a little distilled water. Inspection process 1. Take a test tube of 16mm×100mm, add 0.5ml of serum (pulp), then add 4.5ml of 35mmol/L tungstic acid solution, and mix well. Centrifuge at 3000r/min for 10min, and take the supernatant for use. 2. Take another three test tubes, respectively indicating the measuring tube "U", the standard tube "S", and the blank tube "B". 3. Add protein-free blood filtrate to the measuring tube, add 3.0 ml of creatinine standard application solution to the standard tube, add 3.0 ml of distilled water to the blank tube, then add 1.04 mol/L picric acid reagent 1.0 ml to each tube, and add 0.75 mol/L hydrogen. 1.0 ml of sodium oxide solution. 4. Mix the mixture upside down and place it for 15 minutes. At a wavelength of 510 nm, use a spectrophotometer and adjust the “0” with a blank tube to read the absorbance of the measuring tube and the standard tube. Not suitable for the crowd Generally no taboos. Adverse reactions and risks Generally no complications.

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